Around the world, millions of machines for preparing hot beverages, such as coffee machines, are sold every year. Currently, the energy efficiency of these machines leaves to be desired, while enhancements may be achieved with relatively simple measures such as an auto-power-down mechanism.
An apparatus for preparing hot beverages may operate in at least two, normally successive modes reflecting its primary functions: a brewing mode, and a keep-warm mode. In the former the apparatus executes a brewing cycle in which it brews the beverage, in the latter it keeps the brewed beverage warm for consumption, usually in a thermally non-insulated jug, cup or other vessel placed on a heated keep-warm plate. An auto-power-down mechanism for the apparatus may serve to limit the duration of the keep-warm mode, and to switch the apparatus off, either completely or into a stand-by mode, after a certain delay time that follows the end of a brewing cycle, so as to lower the apparatus' energy consumption. A delay time striking a balance between user comfort and energy efficiency may be on the order of tens of minutes.
In particular in relatively inexpensive machines, such as domestic drip filter coffee machines, it is desirable for an auto-power-down mechanism to be economically implementable.